1. Field of the Invention
The present invention relates to a paper feeder for feeding recording paper automatically in a printer and more particularly to a paper feeder in a printer for separating a plurality of stacked sheets of recording paper one by one and feeding the thus-separated sheets for printing.
2. Description of the Prior Art
Generally, as output devices of computers, word processors and facsimile devices there are used various printers such as thermal printers and page printers.
For performing a desired printing in such printers, plural sheets of recording paper P are stored in a stacked state in storage means which disposed in the body of the printer, then a feed roller is abutted from below against the recording paper P and is rotated, whereby the stacked sheets of recording paper in the storage means are separated and conveyed one by one successively from the sheet located at the lowest position. The recording paper is fed by the feed roller toward a conveyance roller disposed on the front of a printing position of the printer. When the head of the recording paper in the paper feed direction reaches the conveyance roller, the conveyance of the recording paper is taken over by the conveyance roller, which in turn conveys the paper to the printing position.
The storage means in the above conventional printer has a bottom paper guide constituted by a metallic plate which can rest thereon several hundred sheets of recording paper in a stacked state. On a downstream side of the bottom paper guide in the paper feed direction is disposed a feed roller so that the top of the outer peripheral surface of the feed roller is substantially flush with the upper surface of the bottom paper guide to bring the outer peripheral surface into abutment with the recording paper P located at the lowest position. Thus, the feed roller is abutted against the bottom recording paper out of the stacked sheets of recording paper on the bottom paper guide and is then rotated in the paper feed direction to separate only the bottom paper from the paper located just above the bottom paper.
In the conventional paper feeder, the storage means usually stores plural sheets of recording paper in a stacked and substantially horizontal state.
In the conventional paper feeder constructed as above, the upper surface of the bottom recording paper to be fed alone is brought into close contact with the underside of the recording paper located just thereabove and bears a weight load of the stacked sheets of recording paper located thereabove. Therefore, the frictional force acting between adjacent sheets of recording paper may surpass the frictional force between the feed roller and the bottom paper, depending on the rotational force of the feed roller for the separation and conveyance of recording paper, which may result in a failure to effect separation and conveyance of the bottom paper. Thus, such a so-called non-feed error, as well as a so-called double-feed error involving the feed of both bottom paper and the paper located thereabove have heretofore been apt to occur.
Recently, moreover, recording paper for an overhead projector and a surface-coated recording paper has often been used as the aforesaid recording paper P. However, between adjacent sheets of such recording paper there easily occurs a static electricity and the coefficient of friction becomes large, thus easily causing the foregoing non-feed and double-feed errors.